A tubular casting liner for forming a definitive prosthetic socket includes an outer layer defining first and second surfaces and at least one polymeric layer having first and second surfaces. The first outer layer surface continuously defines at least a portion of the exterior surface of the casting liner, and the at least one polymeric layer first surface is secured to the second surface of the outer layer. A ratio of thickness of the at least one polymeric layer at the distal end area relative to the proximal end area is at least 3:1. The casting liner has a substantially straight profile, wherein a diameter d1 of the liner whereat the distal end area begins to transition to close-ended form is the same or substantially the same as a diameter d2 at the proximal end area. A method and kit for forming a definitive prosthetic socket may use the casting liner.
